Forage choppers typically employ chopping "cylinders" which rotate at high speeds and cooperate with stationary shearbars to chop incoming crop stalks and the like into small segments. The relationship of the shearbar to the knives of the cylinder is critical to achieving proper severance and uniform length of chopped segments. Thus, it is essential that the position of the shearbar be adjustable with respect to the chopper so that accommodations can be made as may be necessary or desirable for wear on the part of the knives and the shearbar tending to militate against the quality of chop obtained. In some situations, however, the shearbar is located in an area in which direct access thereto is obstructed by adjacent equipment and structures, making adjustment difficult and tending to discourage proper periodic adjustment. Furthermore, the degree of accuracy and precision involved in prior adjustments has not been all together optimum.